The present invention relates to a device and method for identifying the presence or absence of a leak sealant additive in air conditioning system refrigerant charges, preferably but not exclusively for the purpose of identifying potential damage risk to air conditioning service, repair, diagnostic or other equipment.
Government regulations in the United States, and in many other countries, require the control of refrigerant releases during air conditioning system service and repair due to the potential damaging effects of fluorocarbon refrigerants to atmospheric ozone levels. Fluorocarbon refrigerants, for example R12, R22, R500 and R502, are suspected of presenting an environmental threat due their potential to deplete the earth""s atmospheric ozone layer. Production of these refrigerants has been or is being discontinued by various manufacturers in accordance with the Montreal Protocol. Alternative refrigerants, such as R134a (tetrafluoroethane) for example, are now being utilized that will lessen, but will not totally remove, the potential for atmospheric ozone depletion.
Air conditioning technicians use various service and diagnostic equipment designed to limit the release of all refrigerants to the environment. Such equipment includes, but is not limited to, refrigerant identification analyzers, refrigerant recovery equipment, refrigerant recycling equipment, and refrigerant charging equipment.
Numerous studies of air conditioning servicing and discussions with air conditioning repair technicians indicates that the single largest contributor to refrigerant releases to the atmosphere is air conditioning system leaks. Air conditioning system leaks are also the leading cause of air conditioning system malfunctions in the industry. Air conditioning system leaks contribute to poor air conditioning system performance, increased customer complaints, increased costs to customers due to refrigerant charge replacement, and environmental damage. Costs of refrigerant charge replacement are ever increasing as the cost of original and alternative refrigerants increases.
To lessen the affect of air conditioning system refrigerant leaks upon the customer and the environment, several manufacturers have developed air conditioning system leak sealant additives. These additives come in a variety of formulations from numerous manufacturers. Examples of such leak sealant additives are Super Seal ProTM from Cliplight Manufacturing Company of North York, Ontario, Canada; CRYOsealTM Self-Sealing Kits from Cryo-Chem International of Brunswick, Ga., USA; Keep-It-KoolTM from Mobilair 2000 of Toronto, Ontario, Canada; and R-134a Leak StopTM from Technical Chemical Company of Cleburne, Tex., USA, to name a few. Additionally, virgin refrigerants that contain a leak sealant additive are now available directly from refrigerant manufacturers.
All of these leak sealant additives are designed to seal air conditioning leaks in air conditioning metal components. Specifically, the additives are designed to seal leaks in metal components such as evaporator cores where access is difficult with conventional leak detectors. The additives are typically added to the refrigerant charge as a one or two part liquid and are distributed throughout the air conditioning system via refrigerant circulation by the system compressor. When a leak develops in an air conditioner metal component, the leak sealant additive will be delivered to the leak point by the escaping refrigerant and produce a permanent seal over the leak path, typically in one of two ways. The most common method of seal formation involves the exposure of the sealant to moisture. Moisture is provided by the rapid expansion of refrigerant gas through the leak path, which provides cooling and condensation of atmospheric water vapor at the leak point. Moisture can also be supplied by the condensation that is typically present on all air conditioning system evaporator cores. The additive will then combine with the condensed moisture at the leak to form a permanent seal over the leak path. The other method of seal formation involves the combination of condensed atmospheric water vapor, atmospheric oxygen, and the additive to form a permanent seal over the leak path. Typically, additives that require only exposure to moisture will form a seal on the interior surface of the leak path. Additives that require exposure to moisture and oxygen will typically form a seal within or on the exterior of the leak path. The presence of a leak sealant additive can reduce the environmental impact of refrigerant venting, reduce customer complaints, and limit air conditioning system performance degradation.
However, leak sealant additives can pose difficulties for air conditioning technicians when service is performed upon an air conditioning system that contains a leak sealant additive. The additives will be directly exposed to the diagnostic equipment upon connection to the air conditioning service ports. Since the diagnostic equipment may contain atmospheric water vapor and atmospheric oxygen, the formation of a permanent seal by the additive may be initiated within the equipment itself. Thus, many air conditioning diagnostic tools can be damaged through the clogging of sensing devices, solenoid valves, hoses, gauges, vacuum pumps, etc., by sealant additives. Therefore, air conditioning technicians and manufacturers of air conditioning diagnostic equipment are searching for devices that will either identify the presence of leak sealant additives or provide for their removal to protect expensive diagnostic equipment.
Attempts are currently underway to provide for leak sealant additive removal through filtration. Filtration may involve the removal of refrigerant oil or a liquidxe2x80x94liquid separation filter. Removal of the refrigerant oil from the refrigerant may not serve to totally remove the leak sealant additive since the additives typically are disbursed throughout the refrigerant liquid and vapor phases as well as the refrigerant oil. Liquid-liquid separation may provide an effective method to remove the additives but may require unacceptably high costs to the air conditioning technician. A method of detecting the presence of the leak sealant additive through non-dispersive infrared radiation (NDIR) technology has been developed by the assignee of the present application, Neutronics Incorporated of Exton, Pa., USA. While NDIR technology has provided promising results, it can be expensive.
The present invention utilizes the complete or partial formation of a seal by leak sealant additives and provides a device and method for detecting the presence of sealant additives within an air conditioning system refrigerant charge. The invention is inexpensive, fast, limits refrigerant loss, and easy to use.
The present invention provides a fast, easy, and inexpensive device and method for detecting the presence of a leak sealant additive within an air conditioning system refrigerant charge or within refrigerant stores. The device is capable of detecting any leak sealant additive in any refrigerant type.
One feature of the present invention is the use of a sensing unit having a passage with a calibrated leak path through which refrigerant can flow. The sensing unit includes a seal-forming surface on which any leak sealant additive can quickly form a seal in the presence of water and/or oxygen to at least partially occlude the passage. The sensing unit is used in combination with a coupler for engaging and opening a refrigerant system service port and a flow indicator for detecting the rate at which refrigerant gas flows through the sensing unit.
In use, the sensing unit can be wetted with ordinary water and connected between the service coupler and flow indicator to form a test rig. The test rig is then connected directly to the air conditioning system or refrigerant storage cylinder service port. Refrigerant from the air conditioning system or storage system will flow through the coupler, sensing unit, and flow indicator. If the refrigerant contains a leak sealant additive, the flow indicator will show a reduction or complete stoppage of refrigerant flow over time as the sealant begins to seal the leak path in the sensing unit. If the refrigerant does not contain a leak sealant additive the flow indicator will indicate a substantially constant refrigerant flow rate over time. Thus, the change in refrigerant flow rate through the sensing unit indicates the presence or absence of a leak sealant additive within the tested refrigerant. If refrigerant flow rate diminishes or ceases totally, then a leak sealant additive is present. Conversely, if refrigerant flow rate remains constant, then no leak sealant additive is present in the refrigerant.